1. Field of the Invention
This invention relates in general to subsea well assemblies, and in particular to a metal seal for a tubular connection, such as a stinger in a subsea wellhead.
2. Description of the Prior Art
In subsea well installations, there are instances where tubes interconnect telescopingly but stationarily and provide sealing against high pressure for a long duration. One instance would be a stinger, which is a tube that has a lower end that inserts into a female end or bore of a lower tubular member. The upper end is secured to an upper tubular member. The upper member may be a Christmas tree assembly, and the lower tubular member might be a tubing hanger which is connected to tubing extending into the well. Normally, elastomeric seals are located on the lower end of the stinger for sealing against the bore of the lower tubular member.
The seals must withstand high pressure, and in some cases may be located in place for several years. There is some danger of deterioration and leakage with time. Also, some chemicals may damage elastomeric seals. Metal seals are used at times in various places of the subsea wellhead in place of elastomeric seals, or used with elastomeric seals as a backup. Normally these metal seals require two sealing surfaces. There are also other applications currently using elastomeric seals that preferably could be replaced with metal seals of an improved design.